1. Field of Invention
The present invention relates to an engine, particularly, to an engine including a combustion chamber employing a pre-chamber jet igniter that injects a jet combustion flame, which has been previously formed from an air-fuel mixture, into a space inside the combustion chamber, so that the jet combustion flame serves as a source of ignition of a fuel injected into the space inside the combustion chamber to ignite the fuel, thereby reliably maintaining combustion by use of the jet combustion flame as a large flame kernel and thus remarkably improving fuel consumption and reducing the generation of NOx.
2. Description of Related Art
In general engines, after fuel is directly injected into a combustion chamber (GDI type) or fuel and air are mixed and then supplied to the combustion chamber (MPI type), a combustion flame kernel is created in the combustion chamber by sparks generated from a spark plug, thereby igniting and exploding the air-fuel mixture (flame propagation).
There is a difference between the MPI type and the GDI type in that, in the case in which the fuel is directly injected into the combustion chamber (GDI type), stratified charge combustion is performed, while in the case in which the fuel and the air are mixed and supplied to the combustion chamber (MPI type), homogenous combustion is performed.
Since a explosion stroke is driven by ignition and explosion (flame propagation) in the combustion chamber, power is generated from the engine.
However, if the spark plug generates the ignition sparks in the combustion chamber and the combustion flame kernel is created by the ignition flame in the combustion chamber, the size of the flame kernel is small, and its duration is short, which does not ensure complete combustion in the combustion chamber.
This problem imposes an inherent limit on the above-described combustion schemes.
In order to overcome this limit, lean burn (super lean burn) combustion can be applied to the engine, but the lean burn (super lean burn) combustion has another problem in that a large quantity of NOx is generated due to the high heat of combustion for improving fuel consumption.
In this instance, the generation of NOx can be decreased using DeNOx catalysts, but DeNOx catalysts are expensive, and thus increase costs, and decrease competitiveness.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.